Wear properties of stir cast and hot extruded Mg-6Zn-1Ca/Al2O3p composites.

Magnesium alloys and composites, because of their notable properties, are currently being investigated to open out widespread applications for different industries. In this study, Mg–6Zn–1Ca alloy matrix composite, with different volume percentages of Al2O3 reinforcing particles, was produced by stir casting followed by hot extrusion. The microstructure of the cast and extruded alloys and composites was characterized using optical and scanning electron microscopes, energy-dispersive X-ray and X-ray diffraction spectroscopies. All produced samples were then undergone hardness and wear experiments. Microstructural observations indicated that Ca2Mg6Zn3 precipitates are often located at the grain boundaries of the α-Mg matrix. The observations also showed that increasing the amount of Al2O3 not only increases the hardness but also improves the wear resistance of both the cast and extruded samples, although wear resistance of the extruded composites was much higher than that of the cast samples. Besides, increasing the extrusion temperature from 350 °C to 400 °C increased the wear rate, and the composites extruded at 350 °C possessed the best wear resistance among samples. The results also showed that a combination of the abrasive, delamination and adhesive wear mechanisms takes place in composites, although abrasion is the predominant mechanism in the composites extruded at 350 °C. [ABSTRACT FROM AUTHOR]